Method for manufacturing Fe-based sintered alloy member having excellent dimensional accuracy, strength and sliding performance

Abstract

In a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; as needed, Mn: 0.0025 to 1.05 wt % and/or Zn: 0.001 to 0.7 wt %; and a balance of Fe and inevitable impurities by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, in which the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; as needed, Zn: 0.2 to 10 wt % and/or Mn: 0.5 to 15 wt %; and a balance of Cu and inevitable impurities.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength and sliding performance, which is used in manufacturing mechanical parts such as oil pump gears.

2. Description of Related Art

Recently, with the advancements in the methods of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, it is possible to accurately produce various mechanical parts made of an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance in a large amount. As an example of the method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, there is disclosed a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, in which the method comprises the steps of adding 0.01 to 0.20 wt % of an oxide powder such as aluminum oxide, titan oxide, silicon oxide, vanadium oxide, chrome oxide, etc. into a mixture of an Fe powder, a Cu powder, and a graphite powder; and press-forming and sintering the resultant mixture (see Japanese Unexamined Patent Application Publication No. 6-41609).

However, in the Fe-based sintered alloy member manufactured by the above-mentioned method which comprises the steps of adding 0.01 to 0.20 wt % of an oxide powder such as aluminum oxide, titan oxide, silicon oxide, vanadium oxide, chrome oxide, etc. into the mixture of the Fe powder, the Cu powder, and the graphite powder; and press-forming and sintering the resultant mixture, the dimensional accuracy is somewhat improved, but it still desires to be improved along with the strength, hence there is a need for an Fe-based sintered alloy member having even more excellent dimensional accuracy, strength, and sliding performance.

SUMMARY OF THE INVENTION

Therefore, in consideration of the above-mentioned problems, the inventors of the present invention have conducted extensive studies to develop an Fe-based sintered alloy member having even more excellent dimensional accuracy, strength, and sliding performance, and the results are as follows:

(a) In the conventional method of manufacturing the Fe-based sintered alloy member by blending and mixing an Fe powder, a graphite powder, and a Cu powder and by forming and sintering the resultant mixture, when the mixture of an Fe powder, a graphite powder, and a Cu powder is sintered, the Cu powder is melted into a Cu liquid phase, which exhibits excellent wettability with respect to Fe. Accordingly, Cu in the liquid phase infiltrates into the boundary of the Fe powder to weaken the bonding between the particles in the Fe powder, thereby decreasing the strength of the sintered body, which expands the sintered body to deteriorate the dimensional accuracy.

(b) To improve the dimensional accuracy without decreasing the strength, when an Fe powder, a graphite powder, and a Cu alloy powder are mixed, formed and sintered, by using a Cu alloy powder comprising 1 to 10 wt % of Fe and 0.2 to 1 wt % of oxygen instead of the Cu powder as a base powder, the wettability of Fe powder for the liquid phase Cu and an Fe powder decreases and the infiltration of Cu into the boundaries of the Fe powder is suppressed, thereby suppressing the expansion of the sintered body. Therefore, the dimensional accuracy increases and the bonding strength between the particles in the Fe powder does not decrease. Further, when oxygen is added in the state where it is dissolved into the Cu alloy powder, not as a metal oxide, oxygen becomes inspissated at portions with highly-concentrated Cu in the Fe-based sintered alloy member, thereby improving the sliding performance. Therefore, the Fe-based sintered alloy member having a composition comprising 0.5 to 7 wt % of Cu, 0.1 to 0.98 wt % of C, 0.02 to 0.3 wt % of oxygen, and a balance of Fe and inevitable impurities according to the above-mentioned method exhibits excellent dimensional accuracy, strength, and sliding performance.

(c) When a Cu alloy powder used as a base powder comprise 0.5 to 15 wt % of Mn in addition to 1 to 10 wt % of Fe and 0.2 to 1 wt % of oxygen, Mn maintains high the concentration of oxygen contained in the Cu alloy powder. Therefore, the concentration of oxygen in the liquid phase Cu generated during the sintering is increased, the infiltration of Cu in a liquid phase into the Fe powder is suppressed, and the expansion of the sintered body due to the liquid phase Cu is suppressed. As a result, the dimensional accuracy of the sintered body is further enhanced, and the sliding performance of the Fe-based sintered alloy member is improved by the increased concentration of oxygen at the portions with highly-concentrated Cu in the Fe-based sintered alloy member.

(d) When a Cu alloy powder used as a base powder comprise 0.2 to 10 wt % of Zn in addition to 1 to 10 wt % of Fe and 0.2 to 1 wt % of oxygen, Zn maintains high the concentration of oxygen contained in the Cu alloy powder, Zn can be easily diffused into Fe at a low temperature than the liquid phase Cu, and Zn diffused into Fe deteriorates the wettability of the Fe powder for the liquid phase Cu. Therefore, the expansion of the sintered body due to the liquid phase Cu is suppressed, thereby enhancing the dimensional accuracy of the sintered body. Further, decrease in the strength due to the decoupling of an Fe powder caused by the Cu in a liquid phase is prevented. Furthermore, the sliding performance is improved, thereby enhancing seizure resistance.

(1) According to a first aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising:

Cu: 0.5 to 7 wt %;

C: 0.1 to 0.98 wt %;

oxygen: 0.02 to 0.3 wt %; and

a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising:

Fe: 1 to 10 wt %

oxygen: 0.2 to 1 wt %; and

a balance of Cu and inevitable impurities.

(2) According to a second aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising:

Cu: 0.5 to 7 wt %;

C: 0.1 to 0.98 wt %;

oxygen: 0.02 to 0.3 wt %;

Mn: 0.0025 to 1.05 wt %; and

a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising one or two among Fe of 1 to 10 wt %, oxygen of 0.2 to 1 wt %, and Mn of 0.5 to 15 wt %, and a balance of Cu and inevitable impurities.

(3) According to a third aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising:

Cu: 0.5 to 7 wt %;

C: 0.1 to 0.98 wt %;

oxygen: 0.02 to 0.3 wt %;

Zn: 0.001 to 0.7 wt %; and

a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising:

Fe: 1 to 10 wt %

oxygen: 0.2 to 1 wt %;

Zn: 0.2 to 10 wt %; and

a balance of Cu and inevitable impurities.

(4) According to a fourth aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising:

Cu: 0.5 to 7 wt %;

C: 0.1 to 0.98 wt %;

oxygen: 0.02 to 0.3 wt %;

Mn: 0.0025 to 1.05 wt %;

Zn: 0.001 to 0.7 wt %; and

a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture,

wherein the Cu alloy powder blended as the base powder has a composition comprising Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; Mn: 0.5 to 15 wt %; and a balance of Cu and inevitable impurities.

Further, the components of Al and Si have a function of increasing the concentration of oxygen contained in the Cu alloy powder. Therefore, by using Cu alloy powder comprising one or both of Al and Si of 0.01 to 2 wt % in total as a base powder, by blending and mixing the Cu alloy powder with an Fe powder and a graphite powder, and by forming and sintering the resultant mixture, it is possible to manufacture an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities.

Further, it is possible to manufacture an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities.

Further, it is possible to manufacture an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Zn: 0.001 to 0.7 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities.

Further, it is possible to manufacture an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt % Zn: 0.001 to 0.7 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities.

(5) According to a fifth aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

(6) According to a sixth aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: one or two among Fe of 1 to 10 wt %, oxygen of 0.2 to 1 wt %, and Mn of 0.5 to 15 wt %; one or both of Al and Si of 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

(7) According to a seventh aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Zn: 0.001 to 0.7 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

(8) According to an eighth aspect of the invention, there is provided a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; Zn: 0.001 to 0.7 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; Mn: 0.5 to 15 wt %; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

Next, the reason that the composition of a Cu alloy powder used in the method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance is restricted as described above is described.

Fe contained in a Cu alloy powder:

The Fe component contained in the Cu alloy powder used as a base powder within a range of 1 to 10 wt % deteriorates the wettability with respect to an Fe powder rather than a Cu powder, thereby suppressing the expansion of the sintered body due to the liquid phase Cu and increasing the dimensional accuracy of the resultant sintered body. However, when the Fe content in the Cu alloy less than 1 wt %, it is impossible to obtain the above-mentioned desired effect. On the other hand, when the Fe content in the Cu alloy is larger than 10 wt %, the compressibility in compacting undesirably decreases. Therefore, the Fe content contained in the Cu alloy powder was set within a range of 1 to 10 wt %.

Oxygen contained in the Cu alloy powder:

The oxygen component contained in the Cu alloy powder is inspissated at portions with highly-concentrated Cu, thereby enhancing the dimensional accuracy, strength, and sliding performance. However, when the oxygen content is less than 0.2 wt %, it is impossible to increase the concentration of oxygen at the portions with highly-concentrated Cu. On the other hand, when the oxygen content is larger than 1 wt %, the strength of the Fe-based sintered alloy member after sintering is diminished, so that it is not preferable. Therefore, the oxygen content contained in the Cu alloy powder was set within a range of 0.2 to 1 wt %.

Mn contained in the Cu alloy powder:

The Mn component can maintain high the concentration of oxygen in the Cu alloy powder. Therefore, the concentration of oxygen contained in the liquid phase Cu is increased during sintering, the infiltration of Cu in a liquid phase into the Fe powder is further inhibited, and the expansion of the sintered body due to the liquid phase Cu is suppressed, thereby enhancing the dimensional accuracy. The sliding performance of the Fe-based sintered alloy member is improved by the increased concentration of oxygen at the portions with highly-concentrated Cu in the Fe-based sintered alloy member. However, when the Mn content is less than 0.5 wt %, it is impossible to obtain the above-mentioned desired effect. On the other hand, when the Mn content is larger than 15 wt %, the content of Mn contained in the Fe-based sintered alloy member exceeds 1.05 wt % and thus the toughness thereof decreases, so that it is not desirable. Therefore, the content of Mn contained in the Cu alloy powder was set within a range of 0.5 to 15 wt %.

Zn contained in the Cu alloy powder:

The Zn component can maintain high the concentration of oxygen contained in the Cu alloy powder, Zn can be easily diffused into Fe at a low temperature than the liquid phase Cu, and Zn diffused into Fe deteriorates the wettability of the Fe powder for the liquid phase Cu. Therefore, the expansion of the sintered body due to the liquid phase Cu is suppressed, thereby enhancing the dimensional accuracy of the sintered body. Further, the decrease of the strength due to the decoupling caused by the liquid phase Cu is prevented. Furthermore, the sliding performance is improved, thereby enhancing seizure resistance. However, when the Zn content is less than 0.2 wt %, the content of Zn contained in the Fe-based sintered alloy member becomes less than 0.001 wt %. As a result, it is impossible to obtain the above-mentioned desired effect. On the other hand, when the Zn content is larger than 10 wt %, the content of Zn contained in the Fe-based sintered alloy member exceeds 0.7 wt % and thus the toughness thereof decreases, so that it is not desirable. Therefore, the content of Zn contained in the Cu alloy powder was set within a range of 0.2 to 10 wt %.

Al and Si contained in the Cu alloy powder:

Since Al and Si components have a function of increasing the oxygen concentration in the Cu alloy powder, they are added as needed. However, when the Cu alloy powder contain one or both of Al and Si less than 0.01 wt % in total, the content of Al and Si contained in the Fe-based sintered alloy member becomes less than 0.001 wt %. As a result, it is impossible to obtain the above-mentioned desired effect. On the other hand, when the Cu alloy powder contain one or both of Al and Si larger than 2 wt % in total, the content of Al and Si contained in the Fe-based sintered alloy member exceeds 0.14 wt % and the strength thereof decreases, so that it is not desirable. Therefore, the content of Al and Si contained in the Cu alloy powder was set within a range of 0.01 wt % to 2 wt %.

Therefore, the method of manufacturing the Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance according to the present invention comprises the steps of: preparing a Cu alloy powder having compositions described in (1) to (8), an Fe powder, and a graphite powder, as a base powder; blending the base powder in a predetermined amount; mixing the resultant powder with a zinc stearate powder or Ethylene-bis-Amide as a lubricant using a double-cone mixer; press-forming the mixture to form a green compact; and sintering the green compact in a hydrogen atmosphere including nitrogen at a temperature of 1090 to 1300° C. At this time, the sintering temperature ranges more preferably 1100 to 1260° C.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As a base powder, atomized an Fe powder having a mean particle size of 80 μm, a graphite powder having a mean particle size of 15 μm, a Cu alloy powder having a mean particle size and compositions shown in Table 1, a pure Cu powder, and a MnO powder were prepared.

	TABLE 1
	Composition (wt %)
							Cu and
							inevitable
Kind	Fe	O	Mn	Zn	Al	Si	impurities
Cu	A	1.2	0.25	—	—	—	—	balance
alloy	B	4.1	0.36	—	—	—	—	balance
powder	C	9.5	0.52	—	—	—	—	balance
	D	5.2	0.35	0.8	—	—	—	balance
	E	3.8	0.68	6.5	—	—	—	balance
	F	4.5	0.94	14.3	—	—	—	balance
	G	2.9	0.31	—	9.3	—	—	balance
	H	4.1	0.58	—	5.2	—	—	balance
	I	3.7	0.67	—	0.25	—	—	balance
	J	3.3	0.42	1.8	1.5	—	—	balance
	K	3.8	0.81	1.8	7.4	—	—	balance
	L	5.2	0.88	0.58	0.84	—	—	balance
	M	4.4	0.45	—	—	—	0.03	balance
	N	4.7	0.42	—	—	0.03	—	balance
	O	4.1	0.77	—	—	0.93	0.94	balance
	P	4.2	0.49	1.1	3.6	0.06	0.07	balance
	Q	3.7	0.50	7.6	2.2	0.04	0.06	balance
	R	0.5*	0.21	—	—	—	—	balance
	S	11*	0.45	—	—	—	—	balance
	T	3.8	0.1*	—	—	—	—	balance
	U	6.7	1.2*	—	—	—	—	balance

The values attached with symbol * denote that the values are out of the range of the present invention.

The base powder was blended to have a blending composition shown in Tables 2 and 3 and were mixed after adding the zinc stearate powder by amount corresponding to 0.8 wt %, which is a lubricant at the time of mold forming. Then, the resultant mixture was press formed into a rod-like green compact having dimensions of 10 mm in height×10 mm in width×50 mm in length under forming pressure of 600 MPa. The rod-like green compact was sintered in an atmosphere of an endo-thermic gas at a temperature of 1140° C. for 20 minutes to manufacture a rod-like test specimen. Then, the present examples 1 to 17, comparative examples 1 to 4, and conventional example were carried out.

The dimensions of the rod-like test specimens manufactured according to the present examples 1 to 17, comparative examples 1 to 4, and conventional example were measured and dimensional change rate of standard dimensions of the green compacts were measured. Then, the results thereof were shown in Table 2 and 3 and the dimensional accuracy was evaluated. Further, charpy impact values by charpy impact test were measured and then the results thereof were shown in Tables 2 and 3. Further, the rod-like test specimens were machined to manufacture tension test specimens. Then tensile strength thereof was measured and the results thereof were shown in Table 2 and 3.

Further, abrasion test specimens having dimensions of 5 mm in height×3 mm in width×40 mm in length obtained by machining the rod-like test specimens and rings made of SS330 (general-structure rolled steel) having an outer diameter of 45 mm and an inner diameter of 27 mm were prepared. Then, the abrasion test specimen is pressed against the ring which is being rotated with numbers of rotation of 1500 rpm and rotational speed of 3.5 m/second and then pressing load is increased to measure a load by which seizure is generated. The results thereof were shown in Tables 2 and 3.

	TABLE 2
	Blending
	composition of
	base
	powder (wt %)
	Cu alloy	Dimensional	Charpy
	powder			Composition of Fe-based	change	impact	Tensile	Seizure
	shown in	Graphite	Fe	sintered alloy member (wt %)	rate	value	strength	load
Kind	table 1	powder	powder	Cu	C	O	Mn	Zn	Al	Si	Fe	(wt %)	(J/cm2)	(Mpa)	(N)
The	1	A: 6.7	1.15	balance	6.61	0.97	0.07	—	—	—	—	balance	0.15	25	596	686
present	2	B: 3	0.8	balance	2.86	0.93	0.05	—	—	—	—	balance	0.05	18	620	588
examples	3	C: 5	1.1	balance	4.50	0.92	0.11	—	—	—	—	balance	0.14	22	567	686
	4	D: 5	1.1	balance	4.67	0.94	0.07	0.037	—	—	—	balance	0.13	24	537	686
	5	E: 4	1.0	balance	3.54	0.89	0.13	0.26	—	—	—	balance	0.12	20	603	686
	6	F: 7	1.0	balance	5.61	0.87	0.28	1.00	—	—	—	balance	0.15	25	575	980
	7	G: 6	1.0	balance	5.23	0.85	0.06	—	0.551	—	—	balance	0.13	21	623	784
	8	H: 2.5	0.8	balance	2.24	0.72	0.04	—	0.130	—	—	balance	0.04	17	642	588
	9	I: 1.5	0.7	balance	1.41	0.60	0.02	—	0.004	—	—	balance	0.03	19	562	490
	10	J: 2	0.7	balance	1.83	0.61	0.03	0.036	0.028	—	—	balance	0.05	22	580	588
	11	K: 3	0.9	balance	2.56	0.78	0.09	0.051	0.220	—	—	balance	0.04	21	655	686
	12	L: 1	0.2	balance	0.93	0.18	0.03	0.006	0.006	—	—	balance	0.13	17	573	490

	TABLE 3
	Blending
	composition of
	base powder
	(wt %)		Dimen-
	Cu alloy	sional	Charpy		Sei-
	powder	Gra-		Composition of Fe-based	change	impact	tensile	zure
	shown in	phite	Fe	sintered alloy member (wt %)	rate	value	strength	load
Kind	Table 1	powder	powder	Cu	C	O	Mn	Zn	Al	Si	Fe	(wt %)	(J/cm2)	(Mpa)	(N)
The	13	M: 3.5	0.9	balance	2.83	0.79	0.07	—	—	—	0.0011	balance	0.06	18	623	588
present	14	N: 3.5	0.8	balance	2.84	0.70	0.05	—	—	0.0012	—	balance	0.07	18	610	588
examples	15	O: 6.5	1.1	balance	6.03	0.90	0.21	—	—	0.060	0.060	balance	0.14	25	629	980
	16	P: 3	0.8	balance	2.68	0.71	0.05	0.632	0.103	0.0015	0.0021	balance	0.06	21	628	784
	17	Q: 3	0.9	balance	2.58	0.78	0.06	0.227	0.050	0.0011	0.0015	balance	0.02	19	644	882
Compara-	1	R: 3	0.9	balance	2.94	0.77	0.02	—	—	—	—	balance	0.23	12	394	196
tive	2	S: 3	0.9	balance	2.98	0.80	0.05	—	—	—	—	balance	0.15	9	421	294
examples	3	T: 3	0.9	balance	2.65	0.78	0.01	—	—	—	—	balance	0.28	13	410	196
	4	U: 3	0.9	balance	2.83	0.77	0.13	—	—	—	—	balance	0.13	8	346	686
Conven-	Pure Cu:	0.9	balance	2.98	0.80	0.03	—	—	—	—	balance	0.36	7	375	196
tional	3, MNO:
example	0.1

From the results shown in Tables 2 and 3, compared to the test specimen manufactured according to the conventional example, it is evident that the dimensional change rate of the test specimens manufactured according to the present examples 1 to 17 is small, so that the dimensional accuracy thereof is excellent. Further, since the charpy impact value and the tensile strength are high and the amount of abrasion thereof is small, the sliding performance is excellent. However, the test specimens manufactured according to the comparative examples 1 to 4 which use a Cu powder having a composition out of the range of the present invention are inferior in any one of dimensional accuracy, charpy impact value, tensile strength and the amount of abrasion.

EFFECT OF THE INVENTION

As explained above, it is possible to obtain an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance according to the present invention, which can largely contribute to the development of mechanical industry.

Claims

1. A method of manufacturing an Fe-based sintered alloy member, comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; and a balance of Cu and inevitable impurities.

2. A method of manufacturing an Fe-based sintered alloy member comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising one or two among 1 to 10 wt % of Fe, 0.2 to 1 wt % of oxygen, and 0.5 to 15 wt % of Mn; and a balance of Cu and inevitable impurities.

3. A method of manufacturing an Fe-based sintered alloy member comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Zn: 0.001 to 0.7 wt %; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; and a balance of Cu and inevitable impurities.

4. A method of manufacturing an Fe-based sintered alloy member comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; Zn: 0.001 to 0.7 wt %; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; Mn: 0.5 to 15 wt %; and a balance of Cu and inevitable impurities.

5. A method of manufacturing an Fe-based sintered alloy member comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

6. A method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: one or two among 1 to 10 wt % of Fe, 0.2 to 1 wt % of oxygen and 0.5 to 15 wt % of Mn; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

7. A method of manufacturing an Fe-based sintered alloy member comprising: producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Zn: 0.001 to 0.7 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

8. A method of manufacturing an Fe-based sintered alloy member comprising: Producing said Fe-based sintered alloy member having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; Mn: 0.0025 to 1.05 wt %; Zn: 0.001 to 0.7 wt %; one or both of Al and Si: 0.001 to 0.14 wt % in total; and a balance of Fe and inevitable impurities, by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, wherein the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; Zn: 0.2 to 10 wt %; Mn: 0.5 to 15 wt %; one or both of Al and Si: 0.01 to 2 wt % in total; and a balance of Cu and inevitable impurities.

9. The method of manufacturing an Fe-based sintered alloy member according to claim 1, wherein a blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

10. The method of manufacturing an Fe-based sintered alloy member according to claim 2, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

11. The method of manufacturing an Fe-based sintered alloy member according to claim 3, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

12. The method of manufacturing an Fe-based sintered alloy member according to claim 4, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

13. The method of manufacturing an Fe-based sintered alloy member according to claim 5, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

14. The method of manufacturing an Fe-based sintered alloy member according to claim 6, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

15. The method of manufacturing an Fe-based sintered alloy member according to claim 7, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.

16. The method of manufacturing an Fe-based sintered alloy member according to claim 8, wherein the blending ratio of the Fe powder, the graphite powder and the Cu alloy powder is as follows: the graphite powder: 0.1 to 1.2 wt %; the Cu alloy powder: 1 to 7 wt %; and the Fe powder: the balance.